<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>2 获取元素内容</title>
</head>

<body>
  <button>button</button>

  <script>
    let btn = document.querySelector("button")
    btn.onclick = function () {
      console.log(this.innerHTML)
    }
  </script>
</body>

</html>